Polymer electrolyte membrane for fuel cell, membrane electrode assembly and fuel cell including the same

Abstract

Provided are a polymer electrolyte membrane for fuel cells, and a membrane electrode assembly and a fuel cell including the same. More specifically, provided is a polymer electrolyte membrane for fuel cells including a hydrocarbon-based cation exchange resin having hydrogen ion conductivity and fibrous nanoparticles having a hydrophilic group. By using the fibrous nanoparticles having a hydrophilic group in conjunction with the hydrocarbon-based cation exchange resin having hydrogen ion conductivity, it is possible to obtain a polymer electrolyte membrane for fuel cells that exhibits improved gas barrier properties and long-term resistance, without causing deterioration in performance of fuel cells, and a fuel cell including the polymer electrolyte membrane.

Description

[0001]This application is a National Stage Entry of International Application No. PCT / KR2010 / 009040, filed Dec. 17, 2010, and claims the benefit of Korean Application Nos. 10-2009-0126591, filed on Dec. 18, 2009, and 10-2010-0118698, filed on Nov. 26, 2010, which are hereby incorporated by reference in their entirety for all purposes as if fully set forth herein.TECHNICAL FIELD[0002]The present invention relates to a polymer electrolyte membrane for fuel cells to improve mechanical properties of an electrolyte membrane. More specifically, the present invention relates to a polymer electrolyte membrane for fuel cells that comprise fibrous nanoparticles having at least one hydrophilic group, thereby improving mechanical properties thereof, and a membrane electrode assembly and a fuel cell comprising the same.BACKGROUND ART[0003]Recently, the predicted depletion of conventional energy sources such as oil and coal has brought about an increasing interest in alternative energy sources. I...

AI Technical Summary

Benefits of technology

The invention provides a polymer electrolyte membrane for fuel cells that is made up of fibrous nanoparticles with hydrophilic groups. This membrane exhibits improved mechanical properties compared to conventional membranes. The fibrous nanoparticles help reduce stress by synchronizing with swelling and contraction of the cation exchange resin. They also help reduce contraction due to moisture loss in low humidity conditions and improve tensile strength upon exposure to moisture. The membrane is simple to produce and contributes to the improvement in mechanical properties of the produced fuel cells. The fibrous nanoparticles are uniformly dispersed in the cation exchange resin and can be present in a small amount while still improving durability. The membrane electrode assembly for fuel cells greatly improves mechanical strength and resistance during operation.

Problems solved by technology

These fine pores or cracks cause crossover of hydrogen or methanol crossover, thus resulting in deterioration in durability of fuel cells.

However, the perfluorosulfonic acid resin is disadvantageously expensive, thus increasing manufacturing costs of fuel cells.

However, general hydrocarbon electrolyte membranes undergo great variation in volume depending on variation in humidification conditions and are very fragile, and thus, disadvantageously, mechanical resistance during actual operation of fuel cells is difficult to secure.

For example, hydrocarbon membranes are considerably vulnerable in cycle testing including repeated humidification and dehumidification that is a representative method for evaluating mechanical resistance of electrolyte membranes.

However, in a case in which strength of the electrolyte membrane increases, ion exchange capability is generally deteriorated, and the method of filling the porous material exhibits great improvement in resistance, but has problems of great difficulties associated with processes and increase in costs of raw materials.

In particular, hydrocarbon electrolyte membrane resins undergo great variation in volume depending on variation in humidification conditions and thus cannot obtain significant improvement in resistance in spite of using the porous material.

This method disadvantageously impedes a mixing process and, in particular, does not exhibit remarkable effects.

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